Channel access based on uplink virtual queues

ABSTRACT

An access point may receive, from a set of electronic devices, one or more buffer status reports that indicate that at least a subset of the electronic devices have uplink data associated with one or more access categories. In response, the access point may create a group of uplink virtual queues for one or more electronic devices in the subset based on the one or more buffer status reports, where a given uplink virtual queue corresponds to a particular access category and a given electronic device. The access point may start one or more backoff counters with a one-to-one correspondence to uplink virtual queues in the group of uplink virtual queues. When a backoff counter for the given uplink virtual queue reaches zero, the access point may transmit a trigger frame to an electronic device in the subset that corresponds to the given uplink virtual queue.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/343,765, entitled “CHANNEL ACCESS BASED ON UPLINK VIRTUAL QUEUES,”filed May 31, 2016, and U.S. Provisional Application No. 62/352,875,entitled “CHANNEL ACCESS BASED ON UPLINK VIRTUAL QUEUES,” filed Jun. 21,2016, the content of each of which is incorporated herein by referencein its entirety for all purposes.

FIELD

The described embodiments relate, generally, to wireless communicationsamong electronic devices in a wireless local area network (WLAN),including electronic devices and access points, and techniques forcontrolling channel access by transmitting trigger frames from an accesspoint to the electronic devices based on uplink virtual queues.

BACKGROUND

Many wireless local area networks (WLANs), such as those based on acommunication protocol that is compatible with an IEEE 802.11 standard(which is sometimes referred to as ‘Wi-Fi’), involve contention-baseddistributed access systems. For example, Wi-Fi often uses single-usertransmission via enhanced distributed channel access or EDCA. Inparticular, the WLANs are usually contention based because theytypically utilize unlicensed frequency bands or spectra, which areunpredictable and are often subject to interference. Theunpredictability of the interference can make coordination acrossmultiple electronic devices (which are sometimes referred to as‘stations’ or STAs) very challenging (especially for an unmanaged WLAN),and can result in the failure of a collision free period (CFP). However,the use of fully distributed channel access can allow a very simpleraccess point (AP) and a simpler network deployment (relative to acellular network), which can make it easier and cheaper to deploy aWLAN.

Recently, contention-free multi-user transmission in uplink has beenproposed in the IEEE 802.11ax standard. This approach can dramaticallychange how an electronic device accesses the communication medium. Inparticular, an electronic device can transmit without contending for thecommunication medium. Instead, an access point may content thecommunication medium for the electronic device, and may granttransmission opportunities to the electronic device using a triggerframe (which is sometimes referred to as ‘trigger-based access’ or‘trigger-based channel access,’ e.g., uplink multi-user transmission).For example, during trigger-based uplink channel access, an access pointmay sense the communication medium and, as needed, perform backoff onbehalf of potential uplink trigger-access-enabled electronic devices.Then, the access point may send a trigger frame with multi-userallocation information for the electronic devices. In response to thetrigger frame, the electronic devices may send uplink traffic in theallocated-resource units in a synchronized manner in a multi-usertransmission.

In principle, the use of trigger-based access and multi-usertransmission can significantly reduce the contention by the electronicdevices in the WLAN. Consequently, trigger-based access is oftenexpected to result in improved communication performance. However, inorder for the electronic devices in the WLAN to take advantage of uplinkmulti-user transmission, the access point usually needs to send out atrigger frame in a timely manner. If, e.g., because of congestion in theWLAN, this does not occur, then the electronic devices may only be ableto use single-user transmission and the communication performance maynot be improved.

SUMMARY

Some embodiments that relate to an access point that transmits a triggerframe to a set of electronic devices in a WLAN are described. Inparticular, during operation, an interface circuit in the access pointmay receive, from the set of electronic devices, one or more bufferstatus reports that indicate that at least a subset of the set ofelectronic devices have uplink data, where the uplink data areassociated with one or more access categories. In response, the accesspoint may create a group of uplink virtual queues for electronic devicesin the subset based on the one or more buffer status reports, where agiven uplink virtual queue corresponds to a particular access categoryfor which there is pending uplink data at a given electronic device.Then, the access point may start one or more backoff counters with aone-to-one correspondence to uplink virtual queues in the group ofuplink virtual queues. When a given backoff counter for the given uplinkvirtual queue reaches a predefined count value, the access point maytransmit the trigger frame to an electronic device in the subset thatcorresponds to the given uplink virtual queue.

Note that the trigger frame may include information specifying allocatedresource units for the electronic device.

Moreover, the predefined count value may be zero.

Furthermore, the access point may receive a multi-user frametransmission from the electronic device in response to the triggerframe.

Additionally, the access point may be compatible with an Institute ofElectrical and Electronics Engineers (IEEE) standard that includestrigger-based channel access. For example, the IEEE 802.11 standard mayinclude IEEE 802.11ax.

In some embodiments, a contention window used in the one or more backoffcounters is the same as that used by one or more other access points inthe WLAN that are compatible with the IEEE 802.11 standard. However, thecontention window may be smaller than those used by the set ofelectronic devices or one or more legacy access points in the WLAN thatare not compatible with the IEEE 802.11 standard (i.e., that do not usetrigger-based channel access).

Note that the contention window may be based on a number of the otheraccess points in the WLAN that are compatible with the IEEE 802.11standard. For example, the contention window may increase as a number ofthe other access points in the WLAN increases.

Moreover, after the uplink data from the electronic device has beencleared, the access point may remove one or more corresponding uplinkvirtual queues in the group of uplink virtual queues.

Furthermore, the access point may remove a given uplink virtual queueafter a time interval has elapsed since the given uplink virtual queuewas created.

Additionally, when the access point initiates a cascaded operation (inwhich a single backoff occurs at the beginning of the cascadedoperation, followed by downlink, uplink and block acknowledgmentoperations), the access point may have an increased priority foraccessing a channel. This increased priority may be achieved byincreasing a number of backoff counters for the access point, such that,when any of these backoff counters reaches the predefined count value(such as zero), the access point may access the channel. Note that thisoperation may be performed in conjunction with or separately from theaforementioned operations.

In some embodiments, the access point provides a request, during atarget wake time (TWT) negotiation, to disable transmissions by acounterparty (such as the electronic device) or the access point duringa TWT window. This request may be provided by setting a bit or a valuein a field in a management frame (such as a TWT request or a TWTresponse). Moreover, if there a common TWT negotiation for uplink anddownlink traffic, the access point may receive from the counterparty(such as the electronic device) a request that the access point or theelectronic device disable transmissions during the TWT window. Thisrequest may be provided by setting another bit or a value in a field ina management frame (such as the TWT request or the TWT response). Notethat this operation may be performed in conjunction with or separatelyfrom the aforementioned operations.

Other embodiments include operation with or by the electronic device.

Other embodiments provide an interface circuit in the access point orthe electronic device.

Other embodiments provide a computer-program product for use with theinterface circuit in the access point and/or the electronic device. Thiscomputer-program product includes instructions for at least some of theaforementioned operations performed by the interface circuit in theaccess point or the electronic device.

Other embodiments provide a method for transmitting a trigger frame. Themethod includes at least some of the aforementioned operations performedby the interface circuit in the access point or the electronic device.

This Summary is provided for purposes of illustrating some exemplaryembodiments, so as to provide a basic understanding of some aspects ofthe subject matter described herein. Accordingly, it will be appreciatedthat the above-described features are only examples and should not beconstrued to narrow the scope or spirit of the subject matter describedherein in any way. Other features, aspects, and advantages of thesubject matter described herein will become apparent from the followingDetailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The included drawings are for illustrative purposes and serve only toprovide examples of possible structures and arrangements for thedisclosed systems and techniques for intelligently and efficientlymanaging communication between multiple associated user devices. Thesedrawings in no way limit any changes in form and detail that may be madeto the embodiments by one skilled in the art without departing from thespirit and scope of the embodiments. The embodiments will be readilyunderstood by the following detailed description in conjunction with theaccompanying drawings, wherein like reference numerals designate likestructural elements.

FIG. 1 is a block diagram illustrating an example of electronic devicescommunicating wirelessly.

FIG. 2 is a flow diagram illustrating an example of a method fortransmitting a trigger frame using one of the electronic devices in FIG.1.

FIG. 3 is a flow diagram illustrating an example of communicationbetween electronic devices, such as the electronic devices of FIG. 1.

FIG. 4 is a drawing illustrating uplink virtual queues associated withaccess categories and the electronic devices in FIG. 1.

FIG. 5 is a flow diagram illustrating an example of a method fordisabling transmissions using one of the electronic devices in FIG. 1.

FIG. 6 is a flow diagram illustrating an example of communicationbetween electronic devices, such as the electronic devices of FIG. 1.

FIG. 7 is a flow diagram illustrating an example of a method forincreasing a channel-access priority using one of the electronic devicesin FIG. 1.

FIG. 8 is a flow diagram illustrating an example of communicationbetween electronic devices, such as the electronic devices of FIG. 1.

FIG. 9 is a block diagram illustrating an example of one of theelectronic devices of FIG. 1.

Note that like reference numerals refer to corresponding partsthroughout the drawings. Moreover, multiple instances of the same partare designated by a common prefix separated from an instance number by adash.

DETAILED DESCRIPTION

An access point may receive, from a set of electronic devices in a WLAN,one or more buffer status reports that indicate that at least a subsetof the set of electronic devices have uplink data having one or moreassociated access categories. In response, the access point may create agroup of uplink virtual queues for electronic devices in the subsetbased on the one or more buffer status reports, where a given uplinkvirtual queue corresponds to a particular access category for whichthere is pending uplink data at a given electronic device. Then, theaccess point may start one or more backoff counters with a one-to-onecorrespondence to uplink virtual queues in the group of uplink virtualqueues. When a given backoff counter for the given uplink virtual queuereaches a predefined value (such as zero), the access point may transmita trigger frame to an electronic device in the subset that correspondsto the given uplink virtual queue.

By selectively winning the channel on behalf of the electronic devicesin the subset, this communication technique may help ensure timely (orefficient) and fair access to the channel by the subset of theelectronic devices that have uplink data. In the process, thecommunication technique may reduce contention in the WLAN byfacilitating trigger-based channel access and improved communicationperformance in the WLAN. Consequently, the communication technique mayimprove the user experience when using the access point or theelectronic device, and thus may increase customer satisfaction andretention.

Note that the communication technique may be used during wirelesscommunication between electronic devices in accordance with acommunication protocol, such as: an IEEE 802.11 standard (which issometimes referred to as Wi-Fi). For example, the communicationtechnique may be used with IEEE 802.11ax, which is used as anillustrative example in the discussion that follows. However, thiscommunication technique may also be used with a wide variety of othercommunication protocols, and in access points and electronic devices(such as portable electronic devices or mobile devices) that canincorporate multiple different radio access technologies (RATs) toprovide connections through different wireless networks that offerdifferent services and/or capabilities.

In particular, an electronic device can include hardware and software tosupport a wireless personal area network (WPAN) according to a WPANcommunication protocol, such as those standardized by the Bluetooth®Special Interest Group (in Kirkland, Wash.) and/or those developed byApple (in Cupertino, Calif.) that are referred to as an Apple WirelessDirect Link (AWDL). Moreover, the electronic device can communicate via:a wireless wide area network (WWAN), a wireless metro area network(WMAN) a WLAN, near-field communication (NFC), a cellular-telephone ordata network (such as using a third generation (3G) communicationprotocol, a fourth generation (4G) communication protocol, e.g., LongTerm Evolution (LTE), LTE Advanced (LTE-A), a fifth generation (5G)communication protocol, or other present or future developed advancedcellular communication protocol) and/or another communication protocol.In some embodiments, the communication protocol includes a peer-to-peercommunication technique.

The electronic device, in some embodiments, can also operate as part ofa wireless communication system, which can include a set of clientdevices, which can also be referred to as stations, client electronicdevices, or client electronic devices, interconnected to an accesspoint, e.g., as part of a WLAN, and/or to each other, e.g., as part of aWPAN and/or an ‘ad hoc’ wireless network, such as a Wi-Fi directconnection. In some embodiments, the client device can be any electronicdevice that is capable of communicating via a WLAN technology, e.g., inaccordance with a WLAN communication protocol. Furthermore, in someembodiments, the WLAN technology can include a Wi-Fi (or moregenerically a WLAN) wireless communication subsystem or radio, and theWi-Fi radio can implement an IEEE 802.11 technology, such as one or moreof: IEEE 802.11a; IEEE 802.11b; IEEE 802.11g; IEEE 802.11-2007; IEEE802.11n; IEEE 802.11-2012; IEEE 802.11ac; IEEE 802.11ax, or otherpresent or future developed IEEE 802.11 technologies.

In some embodiments, the electronic device can act as a communicationshub that provides access to a WLAN and/or to a WWAN and, thus, to a widevariety of services that can be supported by various applicationsexecuting on the electronic device. Thus, the electronic device mayinclude an ‘access point’ that communicates wirelessly with otherelectronic devices (such as using Wi-Fi), and that provides access toanother network (such as the Internet) via IEEE 802.3 (which issometimes referred to as ‘Ethernet’).

Additionally, it should be understood that the electronic devicesdescribed herein may be configured as multi-mode wireless communicationdevices that are also capable of communicating via different 3G and/orsecond generation (2G) RATs. In these scenarios, a multi-mode electronicdevice or user equipment (UE) can be configured to prefer attachment toLTE networks offering faster data rate throughput, as compared to other3G legacy networks offering lower data rate throughputs. For example, insome implementations, a multi-mode electronic device is configured tofall back to a 3G legacy network, e.g., an Evolved High Speed PacketAccess (HSPA+) network or a Code Division Multiple Access (CDMA) 2000Evolution-Data Only (EV-DO) network, when LTE and LTE-A networks areotherwise unavailable.

In accordance with various embodiments described herein, the terms‘wireless communication device,’ ‘electronic device,’ ‘mobile device,’‘mobile station,’ ‘wireless station,’ ‘wireless access point,’‘station,’ ‘access point’ and ‘user equipment’ (UE) may be used hereinto describe one or more consumer electronic devices that may be capableof performing procedures associated with various embodiments of thedisclosure.

We now describe the communication technique. FIG. 1 presents a blockdiagram illustrating an example of electronic devices communicatingwirelessly. In particular, one or more electronic devices 110 (such as asmartphone, a laptop computer, a notebook computer, a tablet, or anothersuch electronic device, which is sometimes referred to as a ‘primaryelectronic device’) and access point 112 may communicate wirelessly in aWLAN using an IEEE 802.11 communication protocol. Thus, electronicdevices 110 may be associated with access point 112. For example,electronic devices 110 and access point 112 may wirelessly communicatewhile: detecting one another by scanning wireless channels, transmittingand receiving beacons or beacon frames on wireless channels,establishing connections (for example, by transmitting connectrequests), and/or transmitting and receiving packets or frames (whichmay include the request and/or additional information, such as data, aspayloads). Note that access point 112 may provide access to a network,such as the Internet, via an Ethernet protocol, and may be a physicalaccess point or a virtual or ‘software’ access point that is implementedon a computer or an electronic device.

As described further below with reference to FIG. 9, electronic devices110 and access point 112 may include subsystems, such as a networkingsubsystem, a memory subsystem, and a processor subsystem. In addition,electronic devices 110 and access point 112 may include radios 114 inthe networking subsystems. More generally, electronic devices 110 andaccess point 112 can include (or can be included within) any electronicdevices with networking subsystems that enable electronic devices 110and access point 112 to wirelessly communicate with another electronicdevice. This can include transmitting beacons on wireless channels toenable the electronic devices to make initial contact with or to detecteach other, followed by exchanging subsequent data/management frames(such as connect requests) to establish a connection, configure securityoptions (e.g., IPSec), transmit and receive packets or frames via theconnection, etc.

As can be seen in FIG. 1, wireless signals 116 (represented by a jaggedline) are communicated by radios 114-1 and 114-2 in electronic device110-1 and access point 112, respectively. For example, as notedpreviously, electronic device 110-1 and access point 112 may exchangepackets using a Wi-Fi communication protocol in a WLAN. For example, oneor more of electronic devices 110 may transmit one or more frames toaccess point 112 that include one or more buffer status reports thatindicate that at least a subset of electronic devices 110 have uplinkdata, where the uplink data are associated with one or more accesscategories or priorities (such as voice, video, best effort, background,etc.). As illustrated further below with reference to FIGS. 2-4, inresponse access point 112 may create a group of uplink virtual queuesfor electronic devices in the subset based on the one or more bufferstatus reports. Note that a given uplink virtual queue may correspond toa particular access category for which there is pending uplink data at agiven electronic device.

Then, access point 112 may start one or more backoff counters with aone-to-one correspondence to uplink virtual queues in the group ofuplink virtual queues. When a given backoff counter for the given uplinkvirtual queue reaches a predefined count value (such as zero), accesspoint 112 may transmit a trigger frame to an electronic device (such aselectronic device 110-1) in the subset that corresponds to the givenuplink virtual queue. Furthermore, access point 112 may receive amulti-user frame transmission from electronic device 110-1 in responseto the trigger frame.

Note that access point 112 may remove a given uplink virtual queue aftera time interval has elapsed since the given uplink virtual queue wascreated or since a buffer status report indicated that there was nolonger pending uplink data in a corresponding access category at a givenelectronic device. For example, a given uplink virtual queue may beremoved after 1-2 s.

Moreover, as described further below with reference to FIGS. 5 and 6,independently or additionally from one or more of the precedingoperations, access point 112 may provide a request, during a TWTnegotiation with one of electronic devices 110 (such as electronicdevice 110-1), to disable transmissions by a counterparty (i.e.,electronic device 110-1) or to disable its own transmissions (i.e., byaccess point 112) during a TWT window. This request may be provided bysetting a bit or a value in a field in a management frame (such as a TWTrequest or a TWT response). Furthermore, if there a common TWTnegotiation for uplink and downlink traffic, access point 112 mayreceive from the counterparty (such as electronic device 110-1) arequest that access point 112 or electronic device 110-1 disabletransmissions during the TWT window. This request may be provided bysetting another bit or a value in a field in a management frame (such asthe TWT request or the TWT response).

As described further below with reference to FIGS. 7 and 8,independently or additionally from one or more of the precedingoperations, when access point 112 initiates a cascaded operation (inwhich a single backoff occurs at the beginning of the cascadedoperation, followed by downlink, uplink and block acknowledgmentoperations), access point 112 may have an increased priority foraccessing a channel. This increased priority may be achieved byincreasing a number of backoff counters for access point 112, such that,when any of these backoff counters reaches the predefined count value(such as zero), access point 112 may access the channel.

In these ways, the communication technique may allow electronic devices110 and access point 112 to reduce contention in the WLAN and to improvecommunication performance. These capabilities may improve the userexperience when using electronic devices 110.

In the described embodiments, processing a packet or frame in one ofelectronic devices 110 and access point 112 includes: receiving wirelesssignals 116 encoding a packet or a frame; decoding/extracting the packetor frame from received wireless signals 116 to acquire the packet orframe; and processing the packet or frame to determine informationcontained in the packet or frame (such as data in the payload).

In general, the communication via the WLAN in the communicationtechnique may be characterized by a variety of communication-performancemetrics. For example, the communication-performance metric may include:a received signal strength (RSS), a data rate, a data rate forsuccessful communication (which is sometimes referred to as a‘throughput’), a latency, an error rate (such as a retry or resendrate), a mean-square error of equalized signals relative to anequalization target, inter-symbol interference, multipath interference,a signal-to-noise ratio (SNR), a width of an eye pattern, a ratio ofnumber of bytes successfully communicated during a time interval (suchas 1-10 s) to an estimated maximum number of bytes that can becommunicated in the time interval (the latter of which is sometimesreferred to as the ‘capacity’ of a communication channel or link),and/or a ratio of an actual data rate to an estimated data rate (whichis sometimes referred to as ‘utilization’).

Although we describe the network environment shown in FIG. 1 as anexample, in alternative embodiments, different numbers and/or types ofelectronic devices may be present. For example, some embodiments mayinclude more or fewer electronic devices. As another example, in otherembodiments, different electronic devices can be transmitting and/orreceiving packets or frames.

FIG. 2 presents a flow diagram illustrating an example method 200 fortransmitting a trigger frame in accordance with some embodiments. Thismethod may be performed by an access point (and, more generally, anelectronic device), such as using an interface circuit in access point112 in FIG. 1. During operation, the access point receives, from a setof electronic devices (which may include one or more electronicdevices), one or more buffer status reports (operation 210) thatindicate that at least a subset of the set of electronic devices haveuplink data, where the uplink data are associated with one or moreaccess categories. Note that the access point may be compatible with anIEEE standard that includes trigger-based channel access. For example,the IEEE 802.11 standard may include IEEE 802.11ax.

In response, the access point may create a group of uplink virtualqueues (operation 212) for electronic devices in the subset based on theone or more buffer status reports, where a given uplink virtual queuecorresponds to a particular access category for which there is pendinguplink data at a given electronic device. Note that the group mayinclude one or more uplink virtual queues.

The access point may start one or more backoff counters (operation 214)with a one-to-one correspondence to uplink virtual queues in the groupof uplink virtual queues. In some embodiments, a contention window usedin the one or more backoff counters is the same as that used by one ormore other access points in the WLAN that are compatible with the IEEE802.11 standard. Moreover, the contention window may be based on anumber of the other access points in the WLAN that are compatible withthe IEEE 802.11 standard. For example, the contention window mayincrease as a number of the other access points in the WLAN increases.Furthermore, the contention window may be smaller than those used by theset of electronic devices or one or more legacy access points in theWLAN that are not compatible with the IEEE 802.11 standard (i.e., thatdo not use trigger-based channel access).

When a given backoff counter for the given uplink virtual queue reachesa predefined count value (such as zero, which is used as anillustration), the access point may transmit the trigger frame(operation 216) to an electronic device in the subset that correspondsto the given uplink virtual queue. Note that the trigger frame mayinclude information specifying allocated resource units for theelectronic device.

In some embodiments, the access point optionally performs one or moreadditional operations (operation 218). For example, the access point mayoptionally receive a multi-user frame transmission from the electronicdevice in response to the trigger frame. Alternatively or additionally,after the uplink data from the electronic device has been cleared, theaccess point may remove one or more corresponding uplink virtual queuesin the group of uplink virtual queues. Moreover, the access point mayremove a given uplink virtual queue after a time interval has elapsedsince the given uplink virtual queue was created or since there wasuplink data at the given electronic device for the corresponding accesscategory. Furthermore, the access point may disable transmission by oneor more of the set of electronic devices during the TWT window and/or,during a cascaded operation, may increase its channel-access priority.

In some embodiments of method 200, there may be additional or feweroperations. Moreover, the order of the operations may be changed, and/ortwo or more operations may be combined into a single operation orperformed such that they overlap in time.

In some embodiments, at least some of the operations in method 200 areperformed by interface circuits in the access point or the electronicdevice. For example, at least some of the operations may be performed byfirmware executed by an interface circuit, such as firmware associatedwith a MAC layer, as well as one or more circuits in a physical layer inthe interface circuit.

The communication techniques are further illustrated in FIG. 3, whichpresents a flow diagram illustrating an example of communication betweenelectronic devices 110 and access point 112. In particular, interfacecircuits 310 in electronic devices 110 may transmit one or more bufferstatus reports 312 that indicate that at least a subset of electronicdevices 110 have uplink data, where the uplink data are associated withone or more access categories.

In response, an interface circuit 314 in access point 112 may create agroup of uplink virtual queues 316 for electronic devices in the subsetbased on the one or more buffer status reports 312, where a given uplinkvirtual queue corresponds to a particular access category for whichthere is pending uplink data at a given electronic device.

Then, access point 112 may start one or more backoff counters 318 with aone-to-one correspondence to uplink virtual queues in the group ofuplink virtual queues 316.

When a given backoff counter for the given uplink virtual queue reacheszero (which is used as an illustration), access point 112 may transmit atrigger frame 320 to an electronic device (such as electronic device110-1) in the subset that corresponds to the given uplink virtual queue.

In some embodiments, access point 112 optionally receives a multi-userframe 322 transmission from electronic device 110-1 in response totrigger frame 320. Alternatively or additionally, after the uplink datafrom electronic device 110-1 has been cleared, access point 112 mayremove 324 one or more corresponding uplink virtual queues in the groupof uplink virtual queues 316. Alternatively or additionally, accesspoint 112 may remove 324 one or more of uplink virtual queue 316 after atime interval has elapsed since the given uplink virtual queue wascreated or since there was uplink data pending at electronic devices110-1 and/or 110-2.

We now describe embodiments of the communication technique. In existingcontention-based channel access techniques (such as EDCA), at aparticular electronic device in a WLAN there may be four access queuesand backoff counters, each corresponding to a different access category(such as voice, video, best effort and background). When a particularbackoff counter reaches zero, the electronic device may win the channeland can initiate single-user transmission.

In contrast, in uplink multi-user transmission, because an access pointinitiates the transmission by the electronic devices, the access pointis actually contending for the channel on behalf of the electronicdevices. The disclosed communication technique provides a trigger-basedchannel-access technique for an access point to send a trigger frame. Inparticular, the access point may create virtual queues (which aresometimes referred to as ‘uplink virtual queues’) for uplink electronicdevices that have uplink data traffic. These uplink virtual queues maybe based on one or more buffer status reports from the electronicdevices. Moreover, the access point may create the uplink virtual queuesfor the corresponding access categories that have reported data trafficfrom the electronic devices. For example, if electronic device 1 hasreported data traffic for access categories 1, 2 and 4, correspondinguplink virtual queues may be created by the access point. FIG. 4presents a drawing illustrating an example of uplink virtual queues 410associated with access categories 412 and electronic devices 110 (FIG.1). Moreover, for each of the uplink virtual queues, the access pointmay start a backoff counter. When any of the backoff counters reacheszero, the access point may win the channel on behalf of thecorresponding electronic device and may transmit a trigger frame to oneor more of the electronic devices.

Because the access point may only contend for the channel for thoseelectronic devices that have uplink data traffic, the uplink virtualqueues and the backoff counters may be created on behalf of theseelectronic devices. When a particular backoff counter (such as a backoffcounter for uplink virtual queue 410-1) reaches zero, that particularelectronic device and that particular access category (i.e., accesscategory 412-1 in this example) may be considered to have won thechannel. When the access point sends a trigger frame when this backoffcounter reaches zero, the trigger frame may include informationspecifying resource-unit allocation for the particular electronic deviceand the particular access category to transmit data. Note that theparticular electronic device is sometimes called the “primary electronicdevice” and the particular access category is sometimes called the“primary access category”.

The contention window used in each backoff counter may depend on theneighboring IEEE 802.11ax access points in order to avoid collisionswith other IEEE 802.11ax access points. Moreover, the contention windowmay be chosen or selected such that IEEE 802.11ax access points haveequal priority in sending a trigger frame. However, an IEEE 802.11axaccess point may have higher priority in sending the trigger frame. Notethat the use of multiple backoff counter at the access point sides mayalready create or facilitate such a prioritized access.

Furthermore, IEEE 802.11ax access points may have higher priority thanIEEE 802.11ax stations. This may be facilitated by choosing or selectinga contention window for an IEEE 802.11ax access point that is smallerthan the contention window that is used by an IEEE 802.11ax electronicdevice (or station) or by a legacy IEEE 802.11 electronic device forthis particular access category. For example, if the video accesscategory has a contention window of 31, then the access point may use asmaller contention window size for video. Similarly, an IEEE 802.11axaccess point may have a higher priority than a legacy IEEE 802.11 accesspoint that does not support trigger-based channel access. Thus, the IEEE802.11ax access point may have a smaller contention window for aparticular access category than that used by the legacy IEEE 802.11access point(s).

Therefore, in general, an IEEE 802.11ax access point may use acontention window that is a function of a number of neighboring IEEE802.11ax access points, and the contention window may increase as thenumber of neighboring IEEE 802.11ax access points increases (therebyreducing collisions from multiple access points contending for thechannel. In addition, an IEEE 802.11ax access point may use a smallercontention window value than that used by legacy IEEE 802.11 accesspoints and legacy electronic devices.

Note that the communication technique may be fair and effective. Inparticular, when the number of the electronic devices in a WLANincreases, the probability that the access point will get to access thechannel increases. This allows the access point to scale itstrigger-frame transmission priority based on the number of electronicdevices for which it is attempting to access the channel. Therefore, themore electronic devices the access point needs to contend for, i.e., themore congestion that the access point needs to resolve, the higher thetrigger transmission probability. Furthermore, the contention by theaccess point may be fair by taking other IEEE 802.11ax access pointsinto account. When more access points use high priority to access thechannel, the access point may be more conservative and may not reducecollisions by using a very small contention window.

In summary, the communication technique may provide a trigger-basedchannel access technique for an access point to send a trigger frame. Inthis trigger-based channel access technique, an access point may createan uplink virtual queue when an electronic device reports a buffer foran access category. Note that the access point may destroy an uplinkvirtual queue when the data for the electronic device has been cleared.Moreover, the access point may derive a contention-window size that is afunction of the number of neighboring IEEE 802.11ax access points. Inparticular, the more neighboring IEEE 802.11ax access points, the largerthe contention window. For example, the contention window for aparticular access category may equal a value plus a number ofneighboring IEEE 11ax access points.

In some embodiments, different contention-window sizes are used for atleast some of the different backoff counters and/or for at least some ofthe access categories. However, in other embodiments, the samecontention-window size is used for at least some of the differentbackoff counters and/or for at least some of the access categories.

We now describe additional embodiments of the communication technique,which may be performed separately or in conjunction with one or more ofthe preceding embodiments. FIG. 5 presents a flow diagram illustratingan example method 500 for disabling transmissions in accordance withsome embodiments. This method may be performed by an access point (and,more generally, an electronic device), such as an interface circuit inaccess point 112 in FIG. 1. During operation, the access point mayprovide a request, during a TWT negotiation, to disable transmissions(operation 510) by an electronic device or the access point during a TWTwindow. This request may be provided by setting a bit or a value in afield in a management frame (such as a TWT request or a TWT response).

Moreover, if there a common TWT negotiation for uplink and downlinktraffic, the access point may receive from electronic device 110-1 arequest that the access point or the electronic device disabletransmissions (operation 512) during the TWT window. This request may beprovided by setting another bit or a value in a field in a managementframe (such as the TWT request or the TWT response).

In some embodiments of method 500, there may be additional or feweroperations. Moreover, the order of the operations may be changed, and/ortwo or more operations may be combined into a single operation.

In some embodiments, at least some of the operations in method 500 areperformed by interface circuits in the access point or the electronicdevice. For example, at least some of the operations may be performed byfirmware executed by an interface circuit, such as firmware associatedwith a MAC layer, as well as one or more circuits in a physical layer inthe interface circuit.

The communication techniques are further illustrated in FIG. 6, whichpresents a flow diagram illustrating an example of communication betweenelectronic device 110-1 and access point 112. In particular, interfacecircuit 314 in access point 112 may transmit a TWT request 610 (such asa management frame) with a bit included in a field that indicates thataccess point 112 is requesting, during a TWT negotiation, thatelectronic device 110-1 disable transmissions during one or moresubsequent TWT windows. After interface circuit 310-1 receives TWTrequest 610, interface circuit 310-1 may transmit a TWT response 612that agrees to disable transmissions during the one or more subsequentTWT windows.

Alternatively or additionally, if there a common TWT negotiation foruplink and downlink traffic, interface circuit 310-1 may transmit a TWTrequest 614 with a bit included in a field that indicates thatelectronic device 110-1 is requesting, during the TWT negotiation, thataccess point 112 disable transmissions during the one or more subsequentTWT windows. After interface circuit 314 receives TWT request 614,interface circuit 314 may transmit a TWT response 616 that agrees todisable transmissions during the one or more subsequent TWT windows.

FIG. 7 presents a flow diagram illustrating an example method 700 forincreasing a channel-access priority in accordance with someembodiments. This method may be performed by an access point (and, moregenerally, an electronic device), such as an interface circuit in accesspoint 112 in FIG. 1. During operation, the access point initiates acascaded operation (operation 710). In particular, the access point mayperform a single backoff operation (operation 712) at a beginning of thecascaded operation. In order to increase a priority for the access pointto access a channel during a remainder of the cascaded operation, accesspoint may increase a number of backoff counters (operation 714) or maycreate additional backoff counters. For example, access point may doublea number of backoff counters. When any of these backoff counters reachesa predefined count value (operation 716), the access point may accessthe channel (operation 718). For example, the access point may transmitdownlink data, then the access point may receive uplink data, and theaccess point may transmit a block acknowledgment. In particular, in someembodiments, the backoff counter is used to provide higher prioritychannel access for a trigger frame that initiates transmission of theuplink data.

In some embodiments of method 700, there may be additional or feweroperations. Moreover, the order of the operations may be changed, and/ortwo or more operations may be combined into a single operation.

In some embodiments, at least some of the operations in method 700 areperformed by interface circuits in the access point or the electronicdevice. For example, at least some of the operations may be performed byfirmware executed by an interface circuit, such as firmware associatedwith a MAC layer, as well as one or more circuits in a physical layer inthe interface circuit.

The communication techniques are further illustrated in FIG. 8, whichpresents a flow diagram illustrating an example of communication betweenelectronic device 110-1 and access point 112. In particular, interfacecircuit 314 may perform a backoff operation 810 in a cascaded operation.In order to increase a priority for access point 112 to access achannel, interface circuit 314 may increase a number of backoff counters812.

When any of the backoff counters reaches a predefined count value 816interface circuit 314 may access the channel. For example, interfacecircuit 314 may transmit data 814 to electronic device 110-1. After thepredefined count value 816 is reached, interface circuit 314 maytransmit a trigger frame 818 to electronic device 110-1. After receivingtrigger frame 818, interface circuit 310-1 may transmit data 820 toaccess point 112. Furthermore, after data 820 is received, interfacecircuit 314 may transmit a block acknowledgment 822 to electronic device110-1, thereby completing the cascaded operation.

We now describe additional embodiments of the communication technique.In some embodiments, there may be additional rules for adding and/orremoving virtual uplink queues. The motivation for these rules is so thenumber of virtual uplink queues is representative of the current trafficload in the WLAN. In addition, it is not desirable for an access pointto add virtual uplink queues but to never remove them.

For example, an access point may add a virtual uplink queue once theaccess point receives uplink traffic on an access category from anelectronic device. This virtual uplink queue may be removed based on atimeout. Thus, if there is no uplink traffic from the electronicdevice/access category pair for a period of time (such as 1-2 s), theaccess point may remove this virtual uplink queue.

Moreover, in some embodiments, when there is an access-point-initiatedcascaded operation, the access point may be given increased priority toaccess the channel (which is sometimes referred to as a ‘channel-accesspriority’). In particular, during an access-point-initiated cascadedoperation, the access point may be: sharing a transmission opportunityof the access point with uplink data from one or more triggeredelectronic devices; and/or reducing the number of contentions requiredby only requiring a single backoff at the beginning of the cascadedoperation and then allowing downlink, uplink and block acknowledgmenttransactions or operations. In these embodiments, the access point mayhave an increased priority (such as an increase of 2×) to obtain thechannel access for access-point-initiated cascaded operation.

Furthermore, in some embodiments, transmissions by one or moreelectronic devices or an access point may be disabled in a subsequentTWT window during a TWT negotiation between the one or more electronicdevices and the access point. This disabling of transmissions may beused because the TWT may not work well or may not be very powerefficient if, during a negotiated TWT window, the one or more electronicdevices wake up for the TWT window, but the access point is not able toobtain the channel access (for example, due to a highly congestedchannel). In order to address this challenge (by giving the access pointhigher priority to access the channel to send a trigger frame), theaccess point may add a bit to a management frame during the TWTnegotiation in IEEE 802.11ax of a TWT window that provides the followingindication: a ‘0’ may indicate that an electronic device may notinitiate transmission inside this TWT window; and a ‘1’ may initiatethat the electronic device may transmit inside this TWT window. Notethat in order for the electronic device not to transmit during the TWTwindow, there may need to be agreement between the access point and theelectronic device during the TWT negotiation. In some embodiments, theelectronic device may indicate that it voluntarily will not transmitduring the TWT window. In this case, the electronic device canunilaterally decide not transmit during the TWT window.

In some embodiments, there is a single TWT negotiation for IEEE 802.11axfor both uplink and downlink traffic. This approach may be more powerefficient for the electronic device and the access point, and may takeinto account both traffic patterns (uplink and downlink). In theseembodiments, another bit may be included in the management frame for theaccess point. In particular, a ‘0’ may indicate that the access point isnot allowed to initiate transmissions inside the TWT window; and a ‘1’may indicate that the access point is allowed to initiate transmissionsinside the TWT window. Note that in order for the access point not totransmit during the TWT window, there may need to be agreement betweenthe access point and the electronic device during the TWT negotiation.In some embodiments, the access point may indicate that it voluntarilywill not transmit during the TWT window. In this case, the access pointcan unilaterally decide not transmit during the TWT window.

We now describe embodiments of an electronic device. FIG. 9 presents ablock diagram of an electronic device 900 (which may be an access point,another electronic device, such as a station or a legacy electronicdevice) in accordance with some embodiments. This electronic deviceincludes processing subsystem 910, memory subsystem 912, and networkingsubsystem 914. Processing subsystem 910 includes one or more devicesconfigured to perform computational operations. For example, processingsubsystem 910 can include one or more microprocessors,application-specific integrated circuits (ASICs), microcontrollers,programmable-logic devices, and/or one or more digital signal processors(DSPs).

Memory subsystem 912 includes one or more devices for storing dataand/or instructions for processing subsystem 910 and networkingsubsystem 914. For example, memory subsystem 912 can include dynamicrandom access memory (DRAM), static random access memory (SRAM), aread-only memory (ROM), flash memory, and/or other types of memory. Insome embodiments, instructions for processing subsystem 910 in memorysubsystem 912 include: one or more program modules or sets ofinstructions (such as program module 922 or operating system 924), whichmay be executed by processing subsystem 910. For example, a ROM canstore programs, utilities or processes to be executed in a non-volatilemanner, and DRAM can provide volatile data storage, and may storeinstructions related to the operation of electronic device 900. Notethat the one or more computer programs may constitute a computer-programmechanism, a computer-readable storage medium or software. Moreover,instructions in the various modules in memory subsystem 912 may beimplemented in: a high-level procedural language, an object-orientedprogramming language, and/or in an assembly or machine language.Furthermore, the programming language may be compiled or interpreted,e.g., configurable or configured (which may be used interchangeably inthis discussion), to be executed by processing subsystem 910. In someembodiments, the one or more computer programs are distributed over anetwork-coupled computer system so that the one or more computerprograms are stored and executed in a distributed manner.

In addition, memory subsystem 912 can include mechanisms for controllingaccess to the memory. In some embodiments, memory subsystem 912 includesa memory hierarchy that comprises one or more caches coupled to a memoryin electronic device 900. In some of these embodiments, one or more ofthe caches is located in processing subsystem 910.

In some embodiments, memory subsystem 912 is coupled to one or morehigh-capacity mass-storage devices (not shown). For example, memorysubsystem 912 can be coupled to a magnetic or optical drive, asolid-state drive, or another type of mass-storage device. In theseembodiments, memory subsystem 912 can be used by electronic device 900as fast-access storage for often-used data, while the mass-storagedevice is used to store less frequently used data.

Networking subsystem 914 includes one or more devices configured tocouple to and communicate on a wired and/or wireless network (i.e., toperform network operations), including: control logic 916, an interfacecircuit 918 and a set of antennas 920 (or antenna elements) in anadaptive array that can be selectively turned on and/or off by controllogic 916 to create a variety of optional antenna patterns or ‘beampatterns.’ (While FIG. 9 includes set of antennas 920, in someembodiments electronic device 900 includes one or more nodes, such asnodes 908, e.g., a pad, which can be coupled to set of antennas 920.Thus, electronic device 900 may or may not include set of antennas 920.)For example, networking subsystem 914 can include a Bluetooth™networking system, a cellular networking system (e.g., a 3G/4G/5Gnetwork such as UMTS, LTE, etc.), a universal serial bus (USB)networking system, a networking system based on the standards describedin IEEE 802.11 (e.g., a Wi-Fi® networking system), an Ethernetnetworking system, and/or another networking system.

Networking subsystem 914 includes processors, controllers,radios/antennas, sockets/plugs, and/or other devices used for couplingto, communicating on, and handling data and events for each supportednetworking system. Note that mechanisms used for coupling to,communicating on, and handling data and events on the network for eachnetwork system are sometimes collectively referred to as a ‘networkinterface’ for the network system. Moreover, in some embodiments a‘network’ or a ‘connection’ between the electronic devices does not yetexist. Therefore, electronic device 900 may use the mechanisms innetworking subsystem 914 for performing simple wireless communicationbetween the electronic devices, e.g., transmitting advertising or beaconframes and/or scanning for advertising frames transmitted by otherelectronic devices.

Within electronic device 900, processing subsystem 910, memory subsystem912, and networking subsystem 914 are coupled together using bus 928that facilitates data transfer between these components. Bus 928 mayinclude an electrical, optical, and/or electro-optical connection thatthe subsystems can use to communicate commands and data among oneanother. Although only one bus 928 is shown for clarity, differentembodiments can include a different number or configuration ofelectrical, optical, and/or electro-optical connections among thesubsystems.

In some embodiments, electronic device 900 includes a display subsystem926 for displaying information on a display, which may include a displaydriver and the display, such as a liquid-crystal display, a multi-touchtouchscreen, etc. Display subsystem 926 may be controlled by processingsubsystem 910 to display information to a user (e.g., informationrelating to incoming, outgoing, or an active communication session).

Electronic device 900 can also include a user-input subsystem 930 thatallows a user of the electronic device 900 to interact with electronicdevice 900. For example, user-input subsystem 930 can take a variety offorms, such as: a button, keypad, dial, touch screen, audio inputinterface, visual/image capture input interface, input in the form ofsensor data, etc.

Electronic device 900 can be (or can be included in) any electronicdevice with at least one network interface. For example, electronicdevice 900 may include: a cellular telephone or a smartphone, a tabletcomputer, a laptop computer, a notebook computer, a personal or desktopcomputer, a netbook computer, a media player device, an electronic bookdevice, a MiFi® device, a smartwatch, a wearable computing device, aportable computing device, a consumer-electronic device, an accesspoint, a router, a switch, communication equipment, test equipment, aswell as any other type of electronic computing device having wirelesscommunication capability that can include communication via one or morewireless communication protocols.

Although specific components are used to describe electronic device 900,in alternative embodiments, different components and/or subsystems maybe present in electronic device 900. For example, electronic device 900may include one or more additional processing subsystems, memorysubsystems, networking subsystems, and/or display subsystems.Additionally, one or more of the subsystems may not be present inelectronic device 900. Moreover, in some embodiments, electronic device900 may include one or more additional subsystems that are not shown inFIG. 9. Also, although separate subsystems are shown in FIG. 9, in someembodiments some or all of a given subsystem or component can beintegrated into one or more of the other subsystems or component(s) inelectronic device 900. For example, in some embodiments program module922 is included in operating system 924 and/or control logic 916 isincluded in interface circuit 918.

Moreover, the circuits and components in electronic device 900 may beimplemented using any combination of analog and/or digital circuitry,including: bipolar, PMOS and/or NMOS gates or transistors. Furthermore,signals in these embodiments may include digital signals that haveapproximately discrete values and/or analog signals that have continuousvalues. Additionally, components and circuits may be single-ended ordifferential, and power supplies may be unipolar or bipolar.

An integrated circuit (which is sometimes referred to as a‘communication circuit’) may implement some or all of the functionalityof networking subsystem 914. This integrated circuit may includehardware and/or software mechanisms that are used for transmittingwireless signals from electronic device 900 and receiving signals atelectronic device 900 from other electronic devices. Aside from themechanisms herein described, radios are generally known in the art andhence are not described in detail. In general, networking subsystem 914and/or the integrated circuit can include any number of radios. Notethat the radios in multiple-radio embodiments function in a similar wayto the described single-radio embodiments.

In some embodiments, networking subsystem 914 and/or the integratedcircuit include a configuration mechanism (such as one or more hardwareand/or software mechanisms) that configures the radio(s) to transmitand/or receive on a given communication channel (e.g., a given carrierfrequency). For example, in some embodiments, the configurationmechanism can be used to switch the radio from monitoring and/ortransmitting on a given communication channel to monitoring and/ortransmitting on a different communication channel. (Note that‘monitoring’ as used herein comprises receiving signals from otherelectronic devices and possibly performing one or more processingoperations on the received signals)

In some embodiments, an output of a process for designing the integratedcircuit, or a portion of the integrated circuit, which includes one ormore of the circuits described herein may be a computer-readable mediumsuch as, for example, a magnetic tape or an optical or magnetic disk.The computer-readable medium may be encoded with data structures orother information describing circuitry that may be physicallyinstantiated as the integrated circuit or the portion of the integratedcircuit. Although various formats may be used for such encoding, thesedata structures are commonly written in: Caltech Intermediate Format(CIF), Calma GDS II Stream Format (GDSII) or Electronic DesignInterchange Format (EDIF). Those of skill in the art of integratedcircuit design can develop such data structures from schematic diagramsof the type detailed above and the corresponding descriptions and encodethe data structures on the computer-readable medium. Those of skill inthe art of integrated circuit fabrication can use such encoded data tofabricate integrated circuits that include one or more of the circuitsdescribed herein.

While the preceding discussion used a Wi-Fi communication protocol as anillustrative example, in other embodiments a wide variety ofcommunication protocols and, more generally, wireless communicationtechniques may be used. Thus, the communication technique may be used ina variety of network interfaces. Furthermore, while some of theoperations in the preceding embodiments were implemented in hardware orsoftware, in general the operations in the preceding embodiments can beimplemented in a wide variety of configurations and architectures.Therefore, some or all of the operations in the preceding embodimentsmay be performed in hardware, in software or both. For example, at leastsome of the operations in the communication technique may be implementedusing program module 922, operating system 924 (such as a driver forinterface circuit 918) or in firmware in interface circuit 918.Alternatively or additionally, at least some of the operations in thecommunication technique may be implemented in a physical layer, such ashardware in interface circuit 918. In some embodiments, thecommunication technique is implemented, at least in part, in a MAC layerand/or in a physical layer in interface circuit 918. In particular, thecommunication technique may be implemented using lower-MAC firmware thatis executed by interface circuit 918 and backoff counters that areimplemented in hardware.

Furthermore, in general, the communication technique may be used tofacilitate scheduled channel access in time and/or frequency inconjunction with multi-user multiple input multiple output (MU-MIMO)and/or Orthogonal Frequency Division Multiple Access (OFDMA).

In some embodiments, an access point includes one or more nodesconfigured to communicatively couple to an antenna; and an interfacecircuit, communicatively coupled to the one or more nodes, configured tocommunicate with a set of electronic devices in a wireless local areanetwork (WLAN), and configured to: (i) receive, from the set ofelectronic devices, one or more buffer status reports that indicate thatat least a subset of the set of electronic devices have uplink data, theuplink data having one or more associated access categories; (ii) createa group of uplink virtual queues for electronic devices in the subsetbased at least in part on the one or more buffer status reports, whereina given uplink virtual queue corresponds to a particular access categoryfor which there is pending uplink data at a given electronic device;(iii) start one or more backoff counters with a one-to-onecorrespondence to uplink virtual queues in the group of uplink virtualqueues; and (iv) transmit, when a given backoff counter for the givenuplink virtual queue reaches a predefined count value, a trigger frameto an electronic device in the subset that corresponds to the givenuplink virtual queue.

In some embodiments, the trigger frame includes information specifyingallocated resource units for the electronic device. In some embodiments,the predefined count value is zero. In some embodiments, the interfacecircuit is configured to receive a multi-user frame transmission fromthe electronic device in response to the trigger frame. In someembodiments, the access point is compatible with an Institute ofElectrical and Electronics Engineers (IEEE) standard that includestrigger-based channel access. In some embodiments, the IEEE 802.11standard includes IEEE 802.11ax. In some embodiments, a contentionwindow used in the one or more backoff counters is the same as that usedby one or more other access points in the WLAN that are compatible withan IEEE 802.11 standard that includes trigger-based channel access. Insome embodiments, a contention window used in the one or more backoffcounters is smaller than those used by the set of electronic devices orby one or more legacy access points in the WLAN that are not compatiblewith the IEEE 802.11 standard that includes trigger-based channelaccess. In some embodiments, a contention window used in the one or morebackoff counters is based on a number of other access points in the WLANthat are compatible with an IEEE 802.11 standard that includestrigger-based channel access. In some embodiments, the contention windowincreases in duration as a number of other access points in the WLANincreases. In some embodiments, after the uplink data from theelectronic device has been cleared, the interface circuit is configuredto remove one or more corresponding uplink virtual queues in the groupof uplink virtual queues. In some embodiments, the access point furtherincludes the antenna. In some embodiments, the interface circuit isconfigured to remove the given uplink virtual queue after a timeinterval has elapsed since the given uplink virtual queue was created.In some embodiments, when the interface circuit initiates a cascadedoperation in which a single backoff occurs at the beginning of thecascaded operation, followed by downlink, uplink and blockacknowledgment operations, the interface circuit is configured to createa larger number of backoff counters for the access point in order toincrease a channel-access priority of the access point to access achannel; and when any of the backoff counters reaches the predefinedcount value, the interface circuit is configured to access the channel.In some embodiments, during a target wake time (TWT) negotiation, theinterface circuit is configured to provide a request that the electronicdevice disable transmissions during a subsequent TWT window. In someembodiments, during a common target wake time (TWT) negotiation foruplink and downlink traffic, the interface circuit is configured toreceive, from the electronic device, a TWT request that the interfacecircuit disable transmissions by the access point during a subsequentTWT window.

In some embodiments, a non-transitory computer-readable storage mediumstores instructions that, when executed by an interface circuit includedin a communication device, cause the communication device to transmit atrigger frame, by carrying out one or more operations that include: (i)receiving, from a set of electronic devices in a wireless local areanetwork (WLAN), one or more buffer status reports that indicate that atleast a subset of the set of electronic devices have uplink data, theuplink data having one or more associated access categories; (ii)creating a group of uplink virtual queues for electronic devices in thesubset based on the one or more buffer status reports, wherein a givenuplink virtual queue corresponds to a particular access category forwhich there is pending uplink data at a given electronic device; (iii)starting one or more backoff counters with a one-to-one correspondenceto uplink virtual queues in the group of uplink virtual queues; and (iv)when a given backoff counter for the given uplink virtual queue reachesa predefined count value, transmitting the trigger frame to anelectronic device in the subset that corresponds to the given uplinkvirtual queue, where the communication device is compatible with anInstitute of Electrical and Electronics Engineers (IEEE) standard thatincludes trigger-based channel access.

In some embodiments, the communication device includes an access point.In some embodiments, the trigger frame includes information specifyingallocated resource units for the electronic device. In some embodiments,the one or more operations further include receiving a multi-user frametransmission from the electronic device in response to the triggerframe. In some embodiments, a contention window used in the one or morebackoff counters is the same as that used by one or more other accesspoints in the WLAN that are compatible with an IEEE 802.11 standard thatincludes trigger-based channel access. In some embodiments, a contentionwindow used in the one or more backoff counters is smaller than thoseused by the set of electronic devices or one or more legacy accesspoints in the WLAN that are not compatible with the IEEE 802.11 standardthat includes trigger-based channel access. In some embodiments, acontention window used in the one or more backoff counters is based on anumber of other access points in the WLAN that are compatible with anIEEE 802.11 standard that includes trigger-based channel access.

In some embodiments, a method for transmitting a trigger frame using aninterface circuit in an access point includes: (i) receiving, from a setof electronic devices in a wireless local area network (WLAN), one ormore buffer status reports that indicate that at least a subset of theset of electronic devices have uplink data, the uplink data having oneor more associated access categories; (ii) creating a group of uplinkvirtual queues for electronic devices in the subset based on the one ormore buffer status reports, wherein a given uplink virtual queuecorresponds to a particular access category for which there is pendinguplink data at a given electronic device; (iii) starting one or morebackoff counters with a one-to-one correspondence to uplink virtualqueues in the group of uplink virtual queues; and (iv) when a givenbackoff counter for the given uplink virtual queue reaches a predefinedcount value, transmitting the trigger frame to an electronic device inthe subset that corresponds to the given uplink virtual queue.

In some embodiments, an access point includes: one or more nodesconfigured to communicatively couple to an antenna; and an interfacecircuit, communicatively coupled to the one or more nodes, configured tocommunicate with one or more electronic devices in a wireless local areanetwork (WLAN), and configured to: (i) when the interface circuitinitiates a cascaded operation in which a single backoff occurs at thebeginning of the cascaded operation, followed by downlink, uplink andblock acknowledgment operations, create a larger number of backoffcounters for the access point in order to increase a channel-accesspriority of the access point to access a channel; and (ii) when any ofthe backoff counters reaches a predefined count value, access thechannel.

In some embodiments, a non-transitory computer-readable storage mediumstores instructions that, when executed by an interface circuit includedin a communication device, cause the communication device to increase achannel-access priority, by carrying out one or more operations thatinclude: (i) creating, when the interface circuit initiates a cascadedoperation in which a single backoff occurs at the beginning of thecascaded operation, followed by downlink, uplink and blockacknowledgment operations, multiple backoff counters associated with theaccess point in order to increase a channel-access priority of theaccess point; and (ii) accessing the channel when any of the multiplebackoff counters reaches a predefined count value.

In some embodiments, a method for increasing a channel-access priorityusing an interface circuit in an access point includes: (i) when theinterface circuit initiates a cascaded operation in which a singlebackoff occurs at the beginning of the cascaded operation, followed bydownlink, uplink and block acknowledgment operations, creating a largernumber of backoff counters for the access point in order to increase achannel-access priority of the access point to access a channel; and(ii) when any of the backoff counters reaches a predefined count value,accessing the channel.

In some embodiments, an access point includes one or more nodesconfigured to communicatively couple to an antenna; and an interfacecircuit, communicatively coupled to the one or more nodes, configured tocommunicate with one or more electronic devices in a wireless local areanetwork (WLAN), and configured to: (i) during a target wake time (TWT)negotiation, provide a request that an electronic device disabletransmissions during a subsequent TWT window; or (ii) during a commonTWT negotiation for uplink and downlink traffic, receive, from theelectronic device, a TWT request that the interface circuit disabletransmissions by the access point during a subsequent TWT window.

In some embodiments, a non-transitory computer-readable storage mediumstores instructions that, when executed by an interface circuit includedin a communication device, cause the communication device to disabletransmissions, by carrying out one or more operations that include: (i)during a target wake time (TWT) negotiation, providing a request that anelectronic device disable transmissions during a subsequent TWT window;or (ii) during a common TWT negotiation for uplink and downlink traffic,receiving, from the electronic device, a TWT request that the interfacecircuit disable transmissions by the access point during the subsequentTWT window.

In some embodiments, a method for disabling transmissions using aninterface circuit in an access point includes: (i) during a target waketime (TWT) negotiation, providing a request that an electronic devicedisable transmissions during a subsequent TWT window; or (ii) during acommon TWT negotiation for uplink and downlink traffic, receiving, fromthe electronic device, a TWT request that the interface circuit disabletransmissions by the access point during the subsequent TWT window.

In the preceding description, we refer to ‘some embodiments.’ Note that‘some embodiments’ describes a subset of all of the possibleembodiments, but does not always specify the same subset of embodiments.

The foregoing description is intended to enable any person skilled inthe art to make and use the disclosure, and is provided in the contextof a particular application and its requirements. Moreover, theforegoing descriptions of embodiments of the present disclosure havebeen presented for purposes of illustration and description only. Theyare not intended to be exhaustive or to limit the present disclosure tothe forms disclosed. Accordingly, many modifications and variations willbe apparent to practitioners skilled in the art, and the generalprinciples defined herein may be applied to other embodiments andapplications without departing from the spirit and scope of the presentdisclosure. Additionally, the discussion of the preceding embodiments isnot intended to limit the present disclosure. Thus, the presentdisclosure is not intended to be limited to the embodiments shown, butis to be accorded the widest scope consistent with the principles andfeatures disclosed herein.

What is claimed is:
 1. An access point, comprising: one or more nodesconfigured to communicatively couple to an antenna; and an interfacecircuit, communicatively coupled to the one or more nodes, configured tocommunicate with a set of electronic devices in a wireless local areanetwork (WLAN), and configured to: receive, from the set of electronicdevices, one or more buffer status reports that indicate that at least asubset of the set of electronic devices have uplink data, the uplinkdata having one or more associated access categories; create a group ofuplink virtual queues for electronic devices in the subset based atleast in part on the one or more buffer status reports, wherein a givenuplink virtual queue corresponds to a particular access category forwhich there is pending uplink data at a given electronic device; startone or more backoff counters with a one-to-one correspondence to uplinkvirtual queues in the group of uplink virtual queues; transmit, when agiven backoff counter for the given uplink virtual queue reaches apredefined count value, a trigger frame to an electronic device in thesubset that corresponds to the given uplink virtual queue; and provide,to the electronic device during a target wake time (TWT) negotiation, arequest that the electronic device disable transmissions during asubsequent TWT window.
 2. The access point of claim 1, wherein thetrigger frame includes information specifying allocated resource unitsfor the electronic device.
 3. The access point of claim 1, wherein thepredefined count value is zero.
 4. The access point of claim 1, whereinthe interface circuit is configured to receive a multi-user frametransmission from the electronic device in response to the triggerframe.
 5. The access point of claim 1, wherein the access point iscompatible with an Institute of Electrical and Electronics Engineers(IEEE) standard that includes trigger-based channel access.
 6. Theaccess point of claim 5, wherein the IEEE standard comprises IEEE802.11ax.
 7. The access point of claim 1, wherein a contention windowused in the one or more backoff counters is the same as that used by oneor more other access points in the WLAN that are compatible with an IEEE802.11 standard that includes trigger-based channel access.
 8. Theaccess point of claim 1, wherein a contention window used in the one ormore backoff counters is smaller than those used by the set ofelectronic devices or by one or more legacy access points in the WLANthat are not compatible with an IEEE 802.11 standard that includestrigger-based channel access.
 9. The access point of claim 1, wherein acontention window used in the one or more backoff counters is based on anumber of other access points in the WLAN that are compatible with anIEEE 802.11 standard that includes trigger-based channel access.
 10. Theaccess point of claim 9, wherein the contention window increases induration as a number of other access points in the WLAN increases. 11.The access point of claim 1, wherein, when the interface circuitinitiates a cascaded operation in which a single backoff occurs at abeginning of the cascaded operation, followed by downlink, uplink andblock acknowledgment operations, the interface circuit is configured tocreate a larger number of backoff counters for the access point in orderto increase a channel-access priority of the access point to access achannel; and wherein, when any of the one or more backoff countersreaches the predefined count value, the interface circuit is configuredto access the channel.
 12. The access point of claim 1, wherein, duringa common target wake time (TWT) negotiation for uplink and downlinktraffic, the interface circuit is configured to receive, from theelectronic device, a TWT request that the interface circuit disabletransmissions by the access point during a subsequent TWT window. 13.The access point of claim 1, wherein the interface is configured toremove the given uplink virtual queue after the pending uplink data forthe given uplink virtual queue has cleared or after a time interval haselapsed since the given uplink virtual queue was created.
 14. Anon-transitory computer-readable storage medium storing instructionsthat, when executed by an interface circuit included in a communicationdevice, cause the communication device to transmit a trigger frame, bycarrying out one or more operations that comprise: receiving, from a setof electronic devices in a wireless local area network (WLAN), one ormore buffer status reports that indicate that at least a subset of theset of electronic devices have uplink data, the uplink data having oneor more associated access categories; creating a group of uplink virtualqueues for electronic devices in the subset based on the one or morebuffer status reports, wherein a given uplink virtual queue correspondsto a particular access category for which there is pending uplink dataat a given electronic device; starting one or more backoff counters witha one-to-one correspondence to uplink virtual queues in the group ofuplink virtual queues; when a given backoff counter for the given uplinkvirtual queue reaches a predefined count value, transmitting the triggerframe to an electronic device in the subset that corresponds to thegiven uplink virtual queue, wherein the communication device iscompatible with an Institute of Electrical and Electronics Engineers(IEEE) standard that includes trigger-based channel access; andproviding, to the electronic device during a target wake time (TWT)negotiation, a request that the electronic device disable transmissionsduring a subsequent TWT window.
 15. The non-transitory computer-readablestorage medium of claim 14, wherein a contention window used in the oneor more backoff counters is the same as that used by one or more otheraccess points in the WLAN that are compatible with an IEEE 802.11standard that includes trigger-based channel access.
 16. Thenon-transitory computer-readable storage medium of claim 14, wherein acontention window used in the one or more backoff counters is smallerthan those used by the set of electronic devices or one or more legacyaccess points in the WLAN that are not compatible with an IEEE 802.11standard that includes trigger-based channel access.
 17. Thenon-transitory computer-readable storage medium of claim 14, wherein acontention window used in the one or more backoff counters is based on anumber of other access points in the WLAN that are compatible with anIEEE 802.11 standard that includes trigger-based channel access.
 18. Thenon-transitory computer-readable storage medium of claim 14, wherein thetrigger frame includes information specifying allocated resource unitsfor the electronic device.
 19. The non-transitory computer-readablestorage medium of claim 14, wherein the IEEE standard comprises IEEE802.11ax.
 20. A method for increasing a channel-access priority, themethod comprising: using an interface circuit in an access point:creating, when the interface circuit initiates a cascaded operation inwhich a single backoff occurs at a beginning of the cascaded operation,followed by downlink, uplink and block acknowledgment operations,multiple backoff counters associated with the access point in order toincrease the channel-access priority of the access point; and accessingthe channel when any of the multiple backoff counters reaches apredefined count value.